Switching power supplies are known. See, for example, Marty Brown, "Practical Switching Power Supply Design," copyright 1990 by Academic Press, Inc., 1250 Sixth Avenue, San Diego, Calif. 92101 (hereinafter "Brown"), especially pages 5-6, section 2.1, entitled "Forward-Mode Switching Regulators." It is also known that a buck regulator is a specific type of switching power supply. See, Brown, pages 20-23, section 4.2.1, entitled "The Buck Regulator Topology."
One problem in power supply design is the limit of the source driving the supply. If a power requirement is too large to be handled by any single available source, there are several alternatives including reducing the load, enhancing the source, combining multiple sources, splitting the load into multiple circuits, and increasing power supply efficiency.
In the case of combining multiple sources, it is obvious that some method must be provided to regulate the output of each source. For example, one prior method of load sharing among a plurality of power sources involves equipping each power source with a current-limiting circuit, and then combining the resulting current-limited sources to feed the single load. However, not only is this prior-art approach inefficient, but it requires additional components as well, thus adding expense.
Therefore, there is a need for an improved power signal combining method and apparatus.